worker drones

Worker drones are an overall name for the protohuman species. Under normal circumstances these humanoids are strong sturdy and mental stable, but not intelligent (A result of genetic manipulation). Aivitu did expect or calculate if you like, with a probability of 0.00003346103% that worker drones could emerge as intelligent biengs. (you think that this probability is low, on a cosmic scale it is significant.)

the protohumans have regenerative capabilities, can think and operate individually and have a limited capable hive mind. Limited: to prevent intelligence as result of hive mind. Aivitu has no objection against intelligent life forms. It's just logical (to Aivitu) to keep intelligence low.